In recent years, an electrifying roll, a transferring roll and a developing roll used in a contact electrifying manner have been required to be components coping with an improvement in image quality and operating speed.
Usually, the electrifying roll, the transferring roll and the developing roll need to have, as an electrical property thereof, semi-conductivity. Moreover, these rolls contact a photosensitive body, so that the rolls are desired not to break the photosensitive body easily and also desired to be small in property of contaminating the photosensitive body. Thus, components which use, as a material thereof, a rubbery material are used in many cases.
As a material of the electrifying roll and others, an epichlorohydrin based polymer, which is a semiconducting rubber, is widely used at present because of the electroconductive property thereof. A method for crosslinking the epichlorohydrin based polymer is generally a method of adding, to a monomer therefor, a crosslinking agent and a crosslinking promoter, and then heating the resultant. However, it is known that in the crosslinking method using a crosslinking agent, residues of the added crosslinking agent contaminate the photosensitive body by heat generated at the time of the crosslinking (see Patent Document 1).
Thus, as a material used for electrographic devices such as an electroconductive roll, a material is desired which has semi-conductivity and is small in property of contaminating a photosensitive body.